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Generator Sizing Calculator

Size a backup generator based on your critical loads. Compare portable vs. standby, fuel types, costs, and runtime for any outage scenario.

Backed by EIA data~2 min

Your Inputs

What do you need to power?

Running load1.3 kW
Peak surge4.6 kW
Recommended size2+ kW

Results

Generators That Fit Your Load

24-Hour Outage Scenario
Fuel needed
8.4 gals
Fuel cost
$27

Generator vs. Battery Backup

MetricYouUS Avg
Equipment cost$600$24,150 (3× battery, after ITC)
Fuel cost per outage$27$0 (solar rechargeable)
Auto-start?No (manual)Yes
Run timeUnlimited (with fuel)31 hrs
Noise72 dBSilent
MaintenanceOil, filters, fuel stabilizerNone

Sizing rule: Total running watts + 20% headroom. Ensure surge capacity covers startup loads (motors draw 2–3× running watts momentarily).

Safety: Never run a generator indoors or in an enclosed garage. Use a transfer switch for permanent connections — never backfeed through a wall outlet.

Fuel storage: Gasoline keeps 3–6 months with stabilizer. Diesel keeps 6–12 months. Propane keeps indefinitely. Natural gas has unlimited supply.

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